Kinematics and trajectory analysis of the fixed abrasive lapping process in machining of interdigitated micro-channels on bipolar plates

• Fixed abrasive lapping was used to machine interdigitated micro-channels.
• Kinematic model was developed to simulate trajectories of fixed abrasives.
• Different arraying forms of fixed abrasives were considered and assessed.
• It shows high efficiency and accuracy in machining micro-channels on bipolar plate.
• Bipolar plate with interdigitated micro-channels shows a good cell performance.

The fixed abrasive lapping process is presented to investigate its ability and accuracy in machining of interdigitated micro-channels on bipolar plates that are used in the proton exchange membrane fuel cell. A kinematical equation to describing the relative movement between the fixed abrasive lapping plate and workpiece is developed and used to numerically simulate the trajectories of a single diamond abrasive and fixed diamond abrasives with 17 different arraying forms, respectively. It is shown that the lapping trajectory can be superposed periodically when the rotation ratio is a rational number. By assessing the uniformity of lapping trajectories and opening ratio of the bipolar plate the optimized rotation ratio is obtained which is 1:1, and the best arraying form of the fixed diamond abrasives on the lapping plate has been obtained as well that is the arraying form of C4. Then, a set of fixed abrasive lapping tests were conducted to explore its ability in machining of interdigitated micro-channels on bipolar plates. It is found that larger material removal rate can be achieved by employing bigger lapping pressure and higher rotation speed for both copper and stainless steel samples considered in this study. The maximum cell power density is found to be about 165 mW cm−2 by testing the performance of a single micro fuel cell with a bipolar plate characterized by interdigitated micro-channels that shows a good cell performance.